The only thing I'm wondering about is: Will all unblock requests be
handled before the release (either by an unblock or a refusal)?

That's the plan, yes. As Neil said, we've unfortunately not been as
good as we should have been at saying "no" (we don't like doing it, but
sometimes avoiding it causes bigger issues).

[...]

http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=702722#10
contained a remark from release team that makes me wonder whether
this was regarded as reasonable. If similar bugs (need to upload
debian-gis and debian-science, debian-med is uploaded #696387)
might be delayed (which I perfectly understand) is it possibly a
good idea to increase the severity of these bugs to make sure
that they will be handled before the release. I would not
consider this if you confirm that all unblocks will be really
handled (in whatever way as said above).

That sounds like you're suggesting raising the severity of non-RC bugs
to RC levels just so that they're "on the radar". Whilst that would
indeed be the effect, it would be an abuse of the severity levels and
I'd expect the result to be a quick revert back to a lower level and
less inclination to look at the issue (whether the latter should be the
case is another matter, but at the end of the day we're still people and
it could be difficult to avoid such a reaction).

I have to admit I'm still a little confused as to why these updates
couldn't have been done before the freeze in any case.